Liquid droplet ejecting apparatus, electro-optical device, method of manufacturing the electro-optical device, and electronic apparatus

ABSTRACT

A liquid droplet ejecting apparatus of the present invention includes a cleaning unit, a regular flushing unit, capping unit, and an ejection-amount measuring unit as droplet ejecting head maintenance units used for function maintenance, function recovery, adjustment, or inspection of a liquid ejecting head. The droplet ejecting head maintenance units are arranged in a group in a movable platen as a maintenance-unit installing section. The movable platen is supported by an accessory stand physically separated from a main body.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation patent application of U.S. Ser. No.10/739,920 filed Dec. 18, 2003, claiming priority to JPSN 2002-372955filed Dec. 24, 2002, both of which are hereby incorporated by reference.

FIELD OF THE INVENTION

The present invention relates to a liquid droplet ejecting apparatus, anelectro-optical device, a method of manufacturing the electro-opticaldevice, and an electronic apparatus.

DESCRIPTION OF THE RELATED ART

Industrial liquid droplet ejecting apparatuses (ink-jet imagingapparatuses) are used for manufacturing, for example, color filters forliquid crystal display devices or organic EL (electroluminescent)display devices, or for forming metal wiring lines on substrates, byadapting an ink-jet method (a liquid droplet ejecting method) forink-jet printers.

In the liquid droplet ejecting apparatuses, there is a need forproviding various units (hereinafter, referred to as droplet ejectinghead maintenance units) used for function maintenance, functionrecovery, adjustment, or inspection of droplet ejecting heads (ink-jetheads). The droplet ejecting head maintenance units can include, forexample, a cleaning unit for cleaning a nozzle-formed surface of thedroplet ejecting head, a capping unit for suctioning liquid dischargedfrom the droplet ejecting head, etc.

Since the industrial liquid droplet ejecting apparatuses increase insize with an increase in the size of substrates, however, there is aproblem in that wide installation spaces are necessary within plants.With an increase in size of the liquid droplet ejecting apparatuses,there is a problem in that an installation space should be secured foreach of the various droplet ejecting head maintenance units describedabove.

Therefore, it is desirable to provide a liquid droplet ejectingapparatus in which the entire space for the apparatus can be effectivelyutilized by arranging a plurality of droplet ejecting head maintenanceunits with high spatial efficiency, an electro-optical devicemanufactured using the liquid droplet ejecting apparatus, a method ofmanufacturing an electro-optical device using the liquid dropletejecting apparatus, and an electronic apparatus comprising theelectro-optical device.

SUMMARY OF THE INVENTION

The above object is accomplished by the following present invention.

A liquid droplet ejecting apparatus according to the present inventionincludes: a main body; a work piece mounting unit on which a work pieceis mounted; a droplet ejecting head for ejecting liquid droplets of anejection liquid to the work piece; a relative movement mechanism forrelatively moving the work piece mounting unit and the droplet ejectinghead; and three or more kinds of droplet ejecting head maintenance unitsused for function maintenance, function recovery, adjustment, orinspection of the droplet ejecting head, wherein at least three of thedroplet ejecting head maintenance units are arranged in a group in amaintenance-unit installing section. As a result, by arranging theplurality of droplet ejecting head maintenance units with high spatialefficiency, it is possible to provide a liquid droplet ejectingapparatus for which the entire space can be effectively utilized.Further, since maintenance by means of various kinds of droplet ejectinghead maintenance units in the maintenance-unit installing section can beperformed in a group, the cycle time required for one work piece can beshortened, so that it is possible to improve throughput (productionefficiency).

It is preferable that the liquid droplet ejecting apparatus according tothe present invention include four or more kinds of droplet ejectinghead maintenance units, and that at least four droplet ejecting headmaintenance units be arranged in a group in the maintenance-unitinstalling section. As a result, it is possible to more effectivelyutilize the entire space for the apparatus, and to further improvethroughput.

In the liquid droplet ejecting apparatus according to the presentinvention, it is preferable that each of the droplet ejecting headmaintenance units installed in the maintenance-unit installing sectionbe one of a cleaning unit for cleaning a nozzle-formed surface of thedroplet ejecting head, a flushing unit having a liquid receiver forreceiving liquid wastefully ejected by the droplet ejecting head duringa waiting time, a capping unit having a cap for covering a nozzle-formedsurface of the droplet ejecting head while suctioning fluid from thedroplet ejecting head, an ejection-amount measuring unit used formeasuring the amount of liquid droplets ejected from the dropletejecting head, and a dot-omission detecting unit used for inspectingdot-omission of the droplet ejecting head. As a result, by arranging thecleaning unit, the flushing unit, the capping unit, the ejection-amountmeasuring unit, and the dot-omission detecting unit with high spatialefficiency, it is possible to effectively utilize the entire space forthe apparatus.

In the liquid droplet ejecting apparatus according to the presentinvention, it is preferable that the droplet ejecting head maintenanceunits installed in the maintenance-unit installing section be arrangedin parallel in a line. As a result, it is possible to more effectivelyutilize the entire space for the apparatus, and to further improvethroughput.

It is preferable that the liquid droplet ejecting apparatus according tothe present invention further include a maintenance-unit movingmechanism for horizontally moving the maintenance-unit installingsection. As a result, since the degree of freedom regarding the patternin which the droplet ejecting head maintenance units are arranged in themaintenance-unit installing section is enhanced, it is possible to moreeffectively utilize the entire space for the apparatus.

In the liquid droplet ejecting apparatus according to the presentinvention, it is preferable that the droplet ejecting head be detachablyprovided in the main body, and that the maintenance-unit movingmechanism move the maintenance-unit installing section to a positionwhere the droplet ejecting head maintenance units installed in themaintenance-unit installing section do not interfere with the dropletejecting head during the attachment or detachment of the dropletejecting head. As a result, the attachment or detachment of the dropletejecting head can be performed easily, smoothly and rapidly, so that itis possible to improve workability.

In the liquid droplet ejecting apparatus according to the presentinvention, it is preferable that the relative movement mechanismcomprise an Y-axis movement mechanism for moving the work piece mountingunit in a horizontal direction (hereinafter referred to as a ‘Y-axisdirection’) relative to the main body, and an X-axis movement mechanismfor moving the droplet ejecting head in another horizontal direction(hereinafter referred to as an ‘X-axis direction’) perpendicular to theY-axis direction relative to the main body. As a result, various kindsof patterns can be formed (imaged) on the work piece in accordance withits purposes.

In the liquid droplet ejecting apparatus according to the presentinvention, it is preferable that the liquid droplets be ejected to thework piece from the droplet ejecting head while relatively moving thework mounting unit and the droplet ejecting head, using either theY-axis direction or the X-axis direction as the primary scanningdirection and the other as the secondary scanning direction. As aresult, various patterns can be formed (imaged) on the work inaccordance with its purposes.

It is preferable that the liquid droplet ejecting apparatus according tothe present invention further include a maintenance-unit movingmechanism for moving the maintenance-unit installing section in theY-axis direction, and that the droplet ejecting head maintenance unitsinstalled in the maintenance-unit installing section be arranged in aline along the Y-axis direction. As a result, it is possible to moreeffectively utilize the entire space for the apparatus, and to furtherimprove throughput.

It is preferable that the liquid droplet ejecting apparatus according tothe present invention further include a height adjusting mechanism foradjusting the height of the maintenance-unit installing section. As aresult, it is possible to easily cope with a change in height of thedroplet ejecting head due to a change in thickness of the work piece tobe manufactured (processed).

In the liquid droplet ejecting apparatus according to the presentinvention, it is preferable that the work piece mounting unit, thedroplet ejecting head, and the relative movement mechanism be supportedby the main body, and that the maintenance-unit installing section besupported by an accessory stand physically separated from the main body.As a result, vibrations generated from the accessory stand side can beprevented from being transferred to the main body side. As such, it ispossible to avoid an adverse effect on the accuracy of the pattern to beformed (imaged) on the work piece.

In the liquid droplet ejecting apparatus according to the presentinvention, it is preferable that the main body have a surface plate, andthat the work piece mounting unit, the droplet ejecting head, and therelative movement mechanism be supported by the surface plate. As aresult, it is possible to form (image) a pattern with high accuracy onthe work piece.

In the liquid droplet ejecting apparatus according to the presentinvention, it is preferable that a side surface of the accessory standbe provided with relevant piping components used for the liquid dropletejecting apparatus, and that the relevant piping components be providedto not protrude outwardly from the total width of the accessory stand byfixing the relevant piping components to fixed sections provided atpositions receding inwardly from the total width of the accessory stand.As a result, when an operator works in the vicinity of the accessorystand, it is possible to easily and smoothly work without interferencewith the relevant piping components.

In the liquid droplet ejecting apparatus according to the presentinvention, it is preferable that a predetermined pattern be formed onthe work piece by ejecting the liquid droplets from the droplet ejectinghead while relatively moving the work piece mounting unit and thedroplet ejecting head.

As a result, various patterns can be formed (imaged) on the work piecein accordance with its purposes.

An electro-optical device according to the present invention ismanufactured using the liquid droplet ejecting apparatus according tothe present invention. As a result, it is possible to provide anelectro-optical device having high-performance elements on whichpatterns are formed (imaged) with high accuracy, and having a lowmanufacturing cost.

A method of manufacturing an electro-optical device according to thepresent invention employs the liquid droplet ejecting apparatusaccording to the present invention. As a result, it is possible toprovide a method of manufacturing an electro-optical device, whereinpatterns can be formed (imaged) on the work piece with high accuracy,and its manufacturing cost can be reduced.

An electronic apparatus according to the present invention comprises theelectro-optical device according to the present invention. As a result,it is possible to provide an electronic apparatus havinghigh-performance elements, on which patterns are formed (imaged) withhigh accuracy, and having a low manufacturing cost.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view illustrating an embodiment of a liquid dropletejecting apparatus according to a principle of the present invention;

FIG. 2 is a side view illustrating an embodiment of a liquid dropletejecting apparatus according to a principle of the present invention;

FIG. 3 is a plan view illustrating a trestle, a stone surface plate, anda substrate-carrying table according to a principle of the presentinvention;

FIG. 4 is a side view illustrating a trestle, a stone surface plate, anda substrate-carrying table according to a principle of the presentinvention;

FIG. 5 is a plan view illustrating a head unit and an X-axis movementmechanism according to a principle of the present invention;

FIG. 6 is a side view seen from an arrow A in FIG. 5;

FIG. 7 is a front view seen from an arrow B in FIG. 5;

FIG. 8 is a schematic view illustrating a pattern forming operation (animaging operation) according to a principle of the present invention;

FIG. 9 is a perspective view illustrating a tank housing unit accordingto a principle of the present invention;

FIG. 10 is a perspective view illustrating an accessory apparatus in theliquid droplet ejecting apparatus according to a principle of thepresent invention;

FIG. 11 is a side view illustrating the accessory apparatus of theliquid droplet ejecting apparatus according to a principle of thepresent invention;

FIG. 12 is a piping system diagram illustrating an ejection liquidsupply unit, a cleaning solution supply unit, and a liquid dischargingunit according to a principle of the present invention;

FIG. 13 is a diagram schematically illustrating the configuration ofliquid amount detecting means according to a principle of the presentinvention;

FIG. 14 is a perspective view illustrating a roller unit in the cleaningunit according to a principle of the present invention;

FIG. 15 is a perspective view illustrating a capping unit according to aprinciple of the present invention;

FIG. 16 is a cross-sectional view illustrating a state where a cap is incontact with a droplet ejecting head according to a principle of thepresent invention;

FIG. 17 is an absorption piping system diagram including respective capsin the capping unit according to a principle of the present invention;

FIG. 18 is a perspective view illustrating an ejection-amount measuringunit according to a principle of the present invention;

FIG. 19 is a plan view of the liquid droplet ejecting apparatus shown inFIGS. 1 and 2;

FIG. 20 is a plan view of the liquid droplet ejecting apparatus shown inFIGS. 1 and 2;

FIG. 21 is a perspective view illustrating fixed sections provided inthe side surfaces of an accessory stand and relevant piping componentsprovided therein according to a principle of the present invention;

FIG. 22 is a perspective view illustrating the fixed sections providedin the side surfaces of the accessory stand and the relevant pipingcomponents provided therein according to a principle of the presentinvention; and

FIG. 23 is a plan view schematically illustrating another embodiment ofthe liquid droplet ejecting apparatus according to a principle of thepresent invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Now, a liquid droplet ejecting apparatus according to the presentinvention will be described in detail and in conjunction with thepreferred embodiments shown in the accompanying drawings.

FIGS. 1 and 2 are a plan view and a side view illustrating an embodimentof a liquid droplet ejecting apparatus according to the presentinvention, respectively; and FIG. 9 is a perspective view illustrating atank housing unit in the liquid droplet ejecting apparatus shown inFIGS. 1 and 2. Hereinafter, for the purpose of convenient explanation,one horizontal direction (the direction corresponding to the right-leftdirection in FIGS. 1 and 2) is referred to as a ‘Y-axis direction’, andanother horizontal direction (the direction corresponding to an up-downdirection in FIG. 1), perpendicular to the Y-axis direction, is referredto as an ‘X-axis direction’. Further, in the Y-axis direction, movementto the right in FIGS. 1 and 2 is referred to as ‘Y-axis advancement’,and movement to the left in FIGS. 1 and 2 is referred to as ‘Y-axisretreat’. Furthermore, in the X-axis direction, downward movement inFIG. 1 is referred to as ‘X-axis advancement’, and upward movement inFIG. 1 is referred to as ‘X-axis retreat’.

A liquid droplet ejecting system 10 shown in FIGS. 1 and 2 comprises aliquid droplet ejecting apparatus (an ink-jet imaging apparatus) 1having droplet ejecting heads 111 and a chamber (a chamber room) 91 forhousing the liquid droplet ejecting apparatus 1.

The liquid droplet ejecting apparatus 1 is an apparatus for ejectingliquid (liquid to be ejected) such as ink, functional liquid containingtarget materials, etc., in a minute liquid droplet state to a substrateW as a work piece by using an ink-jet method (a liquid droplet ejectingmethod) to form (image) a predetermined pattern, and for manufacturingan organic EL display device or a color filter for a liquid crystaldisplay device, or for forming metal wiring lines on a substrate. Thematerial of the substrate W is not particularly limited, and thesubstrate may include any plate-shaped member, such as a glasssubstrate, a silicon substrate, a flexible substrate, etc.

A work piece in the present invention is not limited to the plate-shapedmember, and may include any member having a flat bottom surface. Forexample, the present invention can be applied to a liquid dropletejecting apparatus, etc., for forming a coating film, such as an opticalthin film, by using a lens as a work piece and ejecting liquid dropletsto the lens. The present invention can be applied particularlypreferably to a relatively large liquid droplet ejecting apparatus 1which can cope with a relatively large work piece (for example, a workpiece having a length and a width ranging from several tens ofcentimeters to several meters).

The liquid droplet ejecting apparatus 1 comprises a main body 2, asubstrate carrying table (a substrate carrying stage) 3 as a work piecemounting unit, a head unit 11 having a plurality of droplet ejectingheads (ink-jet heads) 111, an accessory apparatus (a maintenanceapparatus) 12 provided at the side of the main body 2, a tank housingunit 13, a blow unit 14 for emitting a gas to a substrate W, alength-measuring laser unit 15 for measuring the moved length of thesubstrate carrying table 3, and a dot-omission detecting unit 19.

The ejection liquid to be ejected from the droplet ejecting heads 111 isnot particularly limited, and may include liquid (including a dispersedliquid, such as a suspension, an emulsion, etc.) containing, forexample, the following various materials in addition to an inkcontaining filter materials for a color filter: a light-emittingmaterial for forming an EL light-emitting layer in an organic EL(electroluminescence) device; a fluorescent material for forming afluorescent layer on an electrode in an electron-emitting device; afluorescent material for forming a fluorescent layer in a PDP (PlasmaDisplay Panel) device; an electrophoretic material for forming anelectrophoretic layer in an electrophoresis display device; a bankmaterial for forming a bank on a surface of a substrate W; various kindsof coating materials; a liquid-state electrode material for forming anelectrode; a particle material for forming a spacer for forming a finecell gap between two sheets of substrates; a liquid-state metal materialfor forming a metal wire; a lens material for forming a micro lens; aresist material; and a light-diffusing material for forming a lightdiffusing layer.

As shown in FIG. 2, the main body 2 has a trestle 21 provided on thefloor and a stone surface plate (a surface plate) 22 provided on thetrestle 21. The substrate-carrying table 3 is provided on the stonesurface plate 22 to be movable in the Y-axis direction with respect tothe main body 2. The substrate-carrying table 3 advances and retreats inthe Y-axis direction by means of driving of a linear motor 51.

The substrate W is mounted on the substrate-carrying table 3.

The liquid droplet ejecting apparatus 1 may use substrates W havingvarious sizes and shapes, including substrates ranging from a relativelylarge substrate W, having the same size as the substrate-carrying table3, to a relatively small substrate W that is smaller than thesubstrate-carrying table 3. It is generally preferable that the liquiddroplet ejecting operation be performed in a state where the centers ofthe substrate W and the substrate-carrying table 3 are aligned, but, ina case of the relatively small substrates W, the liquid droplet ejectingoperation may be performed in a state where the substrates arepositioned close to the edge portions of the substrate-carrying table 3.

As shown in FIG. 1, in the vicinities of the two sides along the X-axisdirection of the substrate-carrying table 3, a before-imaging flushingunit 104 for receiving liquid droplets wastefully ejected (also referredto as preliminarily ejected or flushed) from the droplet ejecting heads111 before the ejection of liquid droplets (imaging) to the substrate Wis provided. A suction tube (not shown) is connected to thebefore-imaging flushing unit 104, and the wastefully ejected liquid isrecovered and stored through the suction tube by a liquid dischargingunit 18 to be described later.

The moved length of the substrate-carrying table 3 in the Y-axisdirection is measured by the length-measuring laser unit 15 as a movedlength detecting means. The length-measuring laser unit 15 has alength-measuring laser sensor head 151, a mirror 152, and alength-measuring laser unit body 153 provided on the main body 2 side,and a corner cube 154 provided on the substrate-carrying table 3 side.Laser rays emitted from the length-measuring laser sensor head 151 alongthe X axis are bent by the mirror 152, advance in the Y-axis direction,and are irradiated to the corner cube 154. The reflected ray from thecorner cube 154 returns to the length-measuring laser sensor head 151via the mirror 152. In the liquid droplet ejecting apparatus 1, based onthe moved length (the current position) of the substrate-carrying table3 detected by the length-measuring laser unit 15, the ejection timingfrom the droplet ejecting heads 111 is generated.

A main carriage 61 supporting the head unit 11 is provided in the mainbody 2 to be movable in the X-axis direction in a space above thesubstrate-carrying table 3. The head unit 11, having a plurality ofdroplet ejecting heads 111, advances and retreats in the X-axisdirection, together with the main carriage 61 by way of driving a linearmotor actuator 62 comprising a linear motor and a guide.

In a so-called primary scanning of the droplet ejecting heads 111 in theliquid droplet ejecting apparatus 1 according to the present embodiment,the droplet ejecting heads 111 are driven (the liquid droplets areselectively ejected) on the basis of the ejection timing generated usingthe length-measuring laser unit 15, while moving the substrate-carryingtable 3 in the Y-axis direction. Correspondingly thereto, a so-calledsecondary scanning is performed by means of the movement of the headunit 11 (the droplet ejecting heads 111) in the X-axis direction.

A blow unit 14 for semi-drying the liquid droplets ejected to thesubstrate W is provided in the main body 2. The blow unit 14 has anozzle opened in a slit shape along the X-axis direction, and emits gasto the substrate W from the nozzle while carrying the substrate W in theY-axis direction by means of the substrate-carrying table 3. In theliquid droplet ejecting apparatus 1 according to this embodiment, twoblow units 14 positioned at positions separated from each other in theY-axis direction are provided.

In the vicinity of the main body 2 and the accessory apparatus 12, atank housing unit 13 having a rack 131 is provided. As shown in FIG. 9,a first primary tank (an ejection liquid tank) 401, a second primarytank (an ejection liquid tank) 402, a first cleaning solution tank 501,a second cleaning solution tank 502, a first reuse tank 171, a secondreuse tank 172, a first discharged liquid tank 181, and a seconddischarged liquid tank 182 are provided (housed) on the rack 131 of thetank housing unit 13. (The first discharged liquid tank 181 and thesecond discharged liquid tank 182 are not shown in FIG. 9). Further,although two primary tanks are provided in this embodiment, one primarytank or three or more primary tanks may be provided (the same is alsotrue of other tanks).

The first primary tank 401 and the second primary tank 402 store theejection liquid to be ejected from the droplet ejecting heads 111. Thefirst cleaning solution tank 501 and the second cleaning solution tank502 store the cleaning solution to be supplied to a cleaning unit 81that will be described later. The first reuse tank 171 and the secondreuse tank also 172 store the ejection liquid to be recovered from acapping unit 83 that will be described later. The first dischargedliquid tank 181 and the second discharged liquid tank 182 store theejection liquid ejected from the droplet ejecting heads 111 in thebefore-imaging flushing unit 104, a regular flushing unit 82 that willbe described later, and a dot-omission detecting unit 19 that will alsobe described later.

The first primary tank 401 and the second primary tank 402 can be filledup with the ejection liquid or can be replaced with a full tank whenthey are empty. That is, any one of the replacement (detachment orattachment) or fill-up of the ejection liquid may be performed on thefirst primary tank 401 and the second primary tank 402.

Similarly, the first cleaning solution tank 501 and the second cleaningsolution tank 502 may also be subjected to replacement or fill-up. Thefirst reuse tank 171, the second reuse tank 172, the first dischargedliquid tank 181, and the second discharged liquid tank 182,respectively, may be subjected to replacement with empty tanks, orextraction of the inner liquid when they are full.

As shown in FIG. 1, the dot-omission detecting unit 19 is fixed to aposition which is not superposed with the moving area of thesubstrate-carrying table 3 on the stone surface plate 22; and which isbelow the moving area of the head unit 11. The dot-omission detectingunit 19 performs a dot-omission inspection (an ejection confirminginspection) for inspecting (detecting) a dot-omission resulting from theclogging of an ejecting nozzle of the droplet ejecting head 111. Thedot-omission detecting unit 19 comprises, for example, a light-emittingportion and a light-receiving portion for emitting and receiving a laserray and a dot-omission inspecting liquid receiver.

When the dot-omission inspection is performed, the liquid droplets areejected from respective ejecting nozzles of the droplet ejecting heads111 while the head unit 11 moves in the X-axis direction in a spaceabove the dot-omission detecting unit 19. The dot-omission detectingunit 19 performs the light-emitting and light-receiving process on theejected liquid droplets to optically detect the clogging of the ejectingnozzles and their positions. Liquid (liquid droplet) ejected from thedroplet ejecting head 111 in the dot-omission inspection is received bythe dot-omission inspecting liquid receiver.

A suction tube (not shown) is connected to the bottom of thedot-omission inspecting liquid receiver, and the liquid received by thedot-omission inspecting liquid receiver is restored by a liquiddischarging unit 18, which will be described later, through the suctiontube, and stored in the first discharged liquid tank 181 and the seconddischarged liquid tank 182.

The dot-omission inspection employing the dot-omission detecting unit 19can be performed by, for example, a method described in JapaneseUnexamined Patent Application Publication No. 2002-192740, but it is notlimited to the method and may be performed by other methods.

In the vicinity of the liquid droplet ejecting apparatus 1, a controlunit (control means) 16 is provided. The control unit 16 controls all ofthe elements of the liquid droplet ejecting apparatus 1 and has a CPU(Central Processing Unit) and a memory unit for storing variousprograms, such as programs for executing the control operation of theliquid droplet ejecting apparatus 1, and various data. In theillustrated configuration, the control unit 16 is provided outside thechamber 91 that will be described later.

The liquid droplet ejecting apparatus 1 preferably performs the ejectionof liquid droplets (imaging) on the substrate W in an atmosphere inwhich the temperature and humidity are managed by a chamber unit 9. Thechamber unit 9 has a chamber 91 for housing the liquid droplet ejectingapparatus 1 and an air-conditioning system 92 provided outside thechamber 91. The air conditioning system 92 has a known air-conditionertherein and adjusts the temperature and humidity of air, and transfersthe adjusted air to a space 911 under the roof of the chamber 91 throughan inlet duct 93. The air transferred to the space 911 under the rooffrom the air-conditioning system 92 passes through a filter 912 providedbelow the roof, and goes into the main room 913 of the chamber 91.

In the chamber 91, an auxiliary room 916, in addition to the main room913, is provided by means of partition walls 914 and 915, and the tankhousing unit 13 is provided in the auxiliary room 916. A communicatingportion (a passage) 917 for communication of the main room 913 with theauxiliary room 916 is formed in the partition wall 914.

The auxiliary room 916 is provided with an opening and closing door (anopening and closing portion) 918 to the outside of the chamber 91 (seeFIG. 1). The opening and closing portion of the auxiliary room 916 isnot limited to a hinged door, such as the opening and closing door 918,and may be a sliding door, a shutter, etc.

A discharging outlet for discharging gas in the auxiliary room 916 isformed in the auxiliary room 916, and an outlet duct 94 extendingoutwardly is connected to the discharging outlet. The air in the mainroom 913 flows into the auxiliary room 916 through the communicatingportion 917, and is then discharged to the outside of the chamber unit 9through the outlet duct 94.

Since the temperature and humidity around the liquid droplet ejectingapparatus 1 are managed by means of the chamber unit 9, it is possibleto prevent errors resulting from the expansion and contraction of theelements or the substrate W due to a variation in temperature, and thusto image (form) the pattern with high accuracy on the substrate W withthe liquid droplets. Further, since the tank housing unit 13 is alsoplaced in an environment in which the temperature and humidity aremanaged, a characteristic, such as viscosity of the ejection liquid, isstabilized so that it is possible to form (image) a pattern with highaccuracy with the liquid droplets. Since the infiltration of dust, etc.,into the chamber 91 can be prevented, it is possible to keep thesubstrate W clean.

The inside of the chamber 91 is supplied and filled with a gas otherthan air (for example, an inert gas, such as nitrogen, carbon dioxide,helium, neon, argon, krypton, xenon, radon, etc.) by way of conditioningthe gas, and then, in the atmosphere of the chosen gas, the liquiddroplet ejecting apparatus 1 may be operated.

In the liquid droplet ejecting system 10, the tank housing unit 13 canbe accessed without exposing the main room 913 to the outside by openingthe opening and closing door 918. As a result, since the managedtemperature and humidity around the liquid droplet ejecting apparatus 1are not disturbed in accessing the tank housing unit 13, it is possibleto form (image) a pattern with high accuracy, even immediately afterperforming a replacement of the tanks, a fill-up, or recovery of theliquid. Since it is not necessary to wait until the temperature in themain room 913 or the temperatures of the elements of the liquid dropletejecting apparatus 1 are restored to a managed value after performing areplacement of the tanks, a fill-up, or recovery of the liquid, it ispossible to enhance throughput (production efficiency). As a result, itis very advantageous for mass-producing work pieces, such as substratesW, with high accuracy, and thus it is possible to reduce themanufacturing cost.

FIG. 3 is a plan view illustrating the trestle, the stone surface plate,and the substrate-carrying table in the liquid droplet ejectingapparatus shown in FIGS. 1 and 2; and FIG. 4 is a side view illustratingthe trestle, the stone surface plate, and the substrate-carrying tablein the liquid droplet ejecting apparatus shown in FIGS. 1 and 2.

As shown in FIGS. 3 and 4, the substrate-carrying table 3 and the Y-axismovement mechanism 5 for moving the substrate-carrying table 3 in theY-axis direction are provided on the stone surface plate 22. As shown inFIG. 3, a plurality of suction holes (suctioning portions) 332 forsuctioning and fixing the mounted substrate W are formed in thesubstrate-carrying table 3.

As shown in FIG. 4, the Y-axis movement mechanism 5 has a linear motor51 and an air slider 52. The air slider 52 has a slide guide 521extending in the Y-axis direction on the stone surface plate 22 and aslide block 522 movable along the slide guide 521. The slide block 522has an air-emitting port for emitting air between the slide block andthe slide guide 521, and can be smoothly moved by interposing the airemitted from the air-emitting port between the slide block 522 and theslide guide 521.

A base 108 is fixed onto the slide block 522, and the substrate-carryingtable 3 is fixed onto the base 108 with a 0 axial rotation mechanism 105therebetween. In this way, the substrate-carrying table 3 is supportedby the air slider 52 to be smoothly movable in the Y-axis direction, andcan be moved in the Y-axis direction by means of operating the linearmotor 51. The substrate-carrying table 3 is rotatable within apredetermined range about the vertical 0 axis passing through the centerof the substrate carrying table 3 by means of the θ axial rotationmechanism 105.

Above the Y-axis movement mechanism 5, a pair of band-shaped thin plates101 made of a metal material, such as stainless steel, are provided tocover the Y-axis movement mechanism 5. The thin plates 101 pass througha concave portion (groove) formed in the upper surface of the base 108,and are inserted between the base 108 and the θ axial rotation mechanism105. The ejection liquid ejected from the droplet ejecting heads 111 canbe prevented from being attached to the Y-axis movement mechanism 5 byproviding the thin plates 101, thereby protecting the Y-axis movementmechanism 5.

The stone surface plate 22 is formed out of immaculate stone, and itsupper surface has high flatness. The stone surface plate 22 is excellentin various characteristics, such as stability against a variation in anenvironmental temperature, an attenuation characteristic againstvibration, stability against secular variation (deterioration), andcorrosion resistance against the ejection liquid. In this embodiment, byallowing the substrate-carrying table 3, the Y-axis movement mechanism5, and the X-axis movement mechanism 6, which will be described later,to be supported by the stone surface plate 22, errors due to variationin environmental temperature, vibration and secular variation(deterioration) are small. As such, the relative movement of thesubstrate-carrying table 3 and the head unit 11 (the droplet ejectingheads 111) can be performed with high accuracy, and the high accuracycan be stably maintained. As a result, it is possible to form (image) apattern from the liquid droplets with higher accuracy and withstability. The stone material forming the stone surface plate 22 is notparticularly limited, and may preferably be one of Belfast Black,Rustenberg, Kurnool, and Indian Black. Accordingly, the aforementionedcharacteristics of the stone surface plate 22 can be improved.

The stone surface plate 22 is supported by the trestle 21. The trestle21 has a frame 211 formed of a square shape out of an angle, etc., and aplurality of support legs 212 distributed and arranged under the frame211. Preferably, the trestle 21 has a vibration-proof structureemploying an air spring or a rubber bush, so that vibration from thefloor can be prevented from being transferred to the stone surface plate22.

The stone surface plate 22 is preferably supported by (mounted on) thetrestle 21 in a state not coupled (not fixed) to the trestle 21. As aresult, it is possible to avoid the influence of heat expansion, etc.,generated in the trestle 21 on the stone surface plate 22, so that it ispossible to form (image) a pattern with the liquid droplets with higheraccuracy.

In this embodiment, as seen two-dimensionally, the stone surface plate22 comprises a Y-axis movement mechanism support 221 having alongitudinal rectangular shape in the Y-axis direction, and pillarsupports 222 and 223 protruding toward both sides in the X-axisdirection from middle portions of the longitudinal sides of the Y-axismovement mechanism support 221. As a result, the stone surface plate 22has a cross shape as seen two-dimensionally. In other words, the stonesurface plate 22 has a shape obtained by removing the four cornerportions from a rectangular shape, as seen two-dimensionally. On thepillar supports 222 and 223, four pillars 23 that will be describedlater are provided. That is, the stone surface plate 22 has a shapeobtained by removing portions not formed with the Y-axis movementmechanism 5 and the pillars 23 from a rectangular shape, as seentwo-dimensionally.

As a result, since the weight of the stone surface plate 22 decreasedand the area occupied with the stone surface plate 22 can be reduced, itis possible to facilitate transfer of the liquid droplet ejectingapparatus 1 to an installing place thereof, to reduce the loadresistance of the floor in the installing place of a plant, and todecrease the area occupied with the liquid droplet ejecting system 10 inthe plant. The stone surface plate 22 according to this embodiment maybe made of one stone piece, or may be formed by combining a plurality ofstone pieces.

FIG. 5 is a plan view illustrating the head unit and the X-axis movementmechanism in the liquid droplet ejecting apparatus shown in FIGS. 1 and2, FIG. 6 is a side view as seen from an arrow A in FIG. 5, and FIG. 7is a front view as seen from an arrow B in FIG. 5.

As shown in FIGS. 6 and 7, the total of four pillars 23, of which twopillars are opposite to two pillars through the Y-axis movementmechanism 5, and two parallel bars 24 and 25 extending in the X-axisdirection and supported by the. pillars 23 are provided on the stonesurface plate 22 (the pillar supports 222 and 223). Thesubstrate-carrying table 3 can pass below the bars 24 and 25.

The X-axis movement mechanism 6 for moving the droplet ejecting heads111 (the head unit 11) in the X-axis direction is supported through thebars 24 and 25 by the four pillars 23. As shown in FIG. 5, the X-axismovement mechanism 6 has a main carriage (a head unit support) 61 forsupporting the head unit 11, a linear motor actuator 62 that is providedon the bar 24 and guides and drives the main carriage 61 in the X-axisdirection, and a guide 63 that is provided on the bar 25 and guides themain carriage 61 in the X-axis direction. The main carriage 61 is laidover the linear motor actuator 62 and the guide 63.

In this embodiment, the Y-axis movement mechanism 5 and the X-axismovement mechanism 6 constitute a relative movement mechanism forrelatively moving the substrate-carrying table 3 and the dropletejecting heads 111 (the head unit 11).

The head unit 11 is detachably supported by the main carriage 61. Bymoving the head unit 11 together with the main carriage 61 in the X-axisdirection, the secondary scanning of the droplet ejecting heads 111 isperformed. The head unit 11 is supported by the main carriage 61 througha head unit height adjusting mechanism 20 for adjusting the height ofthe head unit 11 from the main carriage 61. As a result, in accordancewith the thickness of the substrate W, a gap between the nozzle-formedsurfaces of the droplet ejecting heads 111 and the substrate W can beadjusted.

As shown in FIG. 7, the linear motor actuator 62 and the guide 63 extendoutwardly over the pillars 23. Accordingly, the head unit 11 can bemoved over the accessory apparatus 12 that will be described later.

A camera carriage 106 is laid over the linear motor actuator 62 and theguide 63. The camera carriage 106 shares the linear motor actuator 62and the guide 63 with the main carriage 61, and is moved in the X-axisdirection independently from the main carriage 61.

A recognition camera 107 for recognizing images of alignment marksformed at predetermined places on the substrate W is provided in thecamera carriage 106. The recognition camera 107 is suspended downwardlyfrom the camera carriage 106. The recognition camera 107 may be used foranother purpose.

FIG. 8 is a schematic view illustrating a pattern-forming operation (animaging operation) in the liquid droplet ejecting apparatus shown inFIGS. 1 and 2. As shown in FIG. 8, the head unit 11 is provided with aplurality of droplet ejecting heads 111 (twelve in this embodiment). Inthe nozzle-formed surface of each droplet ejecting head 111, a pluralityof ejecting nozzles (holes) for ejecting the liquid droplets are formedto be arranged in one or more lines. In the head unit 11, the twelvedroplet ejecting heads 111 are arranged in the second scanning direction(the X-axis direction) to form two lines in which six droplet ejectingheads are arranged on every line, and the nozzle lines of the dropletejecting heads 111 are positioned obliquely about the secondary scanningdirection.

Each ejecting nozzle of the droplet ejecting heads 111 is provided witha driving part having a piezoelectric element as a driving element (notshown). The control unit 16 controls the driving parts of the dropletejecting heads 111 via a driver (not shown). Accordingly, in the dropletejecting heads 111, the liquid droplets are ejected from predeterminedejecting nozzles of predetermined droplet ejecting heads 111. In thiscase, for example, when a predetermined voltage is applied to apiezoelectric element, the piezoelectric element is deformed (expandedor contracted) to apply pressure to a corresponding pressure room (aliquid room), so that the predetermined amount of liquid droplets isejected from the corresponding ejecting nozzle (an ejecting nozzlecommunicating with the above pressure room).

In the present invention, the droplet ejecting heads 111 are not limitedto the aforementioned configuration, and may have, for example, aconfiguration in which the liquid to be heated are heated and boiled bymeans of a heater as a driving element and then the liquid droplets areejected from the ejecting nozzle by means of its pressure.

The aforementioned arrangement pattern of the droplet ejecting heads 111in the head unit 11 is only an example, and the droplet ejecting heads111 adjacent to each other in each line of heads may be arranged to forman angle of 90° (that is, the adjacent heads form a truncated chevronshape), or the droplet ejecting heads 111 may be arranged such that theheads between the lines of heads form an angle of 90° (that is, theinter-line heads form a truncated chevron shape). At any rate, the dotsof the overall ejecting nozzles of the plural droplet ejecting heads 111should be continuous in the secondary scanning direction.

Further, the droplet ejecting heads 111 may not be positioned obliquelyabout the secondary scanning direction, but, instead, the plurality ofdroplet ejecting heads 111 may be arranged in a zigzag shape, a stepshape, etc. Furthermore, as long as a nozzle line (a dot line) having apredetermined length can be formed, the arrangement may have a singledroplet ejecting head 111. Furthermore, the main carriage 61 may beprovided with a plurality of head units 11.

Next, the entire operation of the liquid droplet ejecting apparatus 1controlled by the control unit 16 will be briefly described. When thesubstrate W is supplied onto the substrate-carrying table 3 and ispositioned (pre-alignment) at a predetermined position on thesubstrate-carrying table 3 by means of a substrate positioning unit (notdescribed) provided in the liquid droplet ejecting apparatus 1, thesubstrate W is suctioned and fixed to the substrate-carrying table 3 viaair suction from the suction holes 332 of the substrate-carrying table3. Next, the recognition camera 107 is moved over the alignment marksformed at a predetermined position (one or more positions) of thesubstrate W by means of movement of the substrate-carrying table 3 andthe camera carriage 106, and then recognizes the alignment marks. On thebasis of a recognition result, the θ axial rotation mechanism 105 isactuated to correct a θ axial rotation angle of the substrate W, andcorrection of positions of the substrate W in the X-axis direction andthe Y-axis direction is performed (main alignment) on the data.

After the alignment process on the substrate W is completed, the liquiddroplet ejecting apparatus 1 starts the process of forming (imaging) apredetermined pattern on the substrate W. This process is carried out byperforming the primary scanning and secondary scanning of the dropletejecting heads 111 (the head unit 11) on the substrate W.

In the liquid droplet ejecting apparatus 1 according to this embodiment,the primary scanning is performed by ejecting the liquid droplets fromthe droplet ejecting heads 111 onto the substrate W while moving thesubstrate W in the Y-axis direction by means of the movement of thesubstrate-carrying table 3, in a state where the head unit 11 is fixed(not moved relatively) to the main body 2. That is, the Y-axis directionis the primary scanning direction in this embodiment.

Primary scanning may be performed during advance (forward movement) ofthe substrate-carrying table 3, during retreat (backward movement) ofthe substrate-carrying table, and during both of advance and retreat(reciprocating movement) of the substrate-carrying table. Further,primary scanning may be performed several times by reciprocating thesubstrate-carrying table 3 several times. Through the primary scanning,the ejection of liquid droplets onto an area of the substrate Wextending in the primary scanning direction with a predetermined width(a width which can be covered with the head unit 11) is completed.

After the primary scanning, secondary scanning is performed. Whileliquid droplets are not being ejected, secondary scanning is performedby moving the head unit 11 by a predetermined width in the X-axisdirection through movement of the main carriage 61. That is, in thisembodiment, the X-axis direction is the secondary scanning direction.

After secondary scanning, primary scanning, described above, isperformed again. Accordingly, the liquid droplets are ejected to an areaadjacent to the area in which the liquid droplets are ejected throughprevious primary scanning.

In this way, by repeatedly and alternately performing the primaryscanning and the secondary scanning, the liquid droplets are ejected tothe entire area of the substrate W, so that it is possible to form(image) a predetermined pattern of the ejected liquid droplets (liquid)on the substrate W.

In the present invention, the primary scanning direction and thesecondary scanning direction may be inverted. That is, primary scanningmay be performed by ejecting the liquid droplets to the substrate Wwhile moving the droplet ejecting head 111 (head unit 11) in the X-axisdirection in a state where the substrate W (the substrate-carrying table3) is fixed, and secondary scanning may be performed by moving thesubstrate W (the substrate-carrying table 3) in the Y-axis directionduring non-ejection of the liquid droplets.

FIGS. 10 and 11 are a perspective view and a side view illustrating theaccessory apparatus of the liquid droplet ejecting apparatus shown inFIGS. 1 and 2, respectively; and FIGS. 19 and 20 are plan viewsillustrating the liquid droplet ejecting apparatus shown in FIGS. 1 and2. Now, with reference to these figures, the accessory apparatus 12 ofthe liquid droplet ejecting apparatus 1 will be described.

The head unit 11 waits at a position above the accessory apparatus 12,for example, during the supply and removal of the substrate W. In thecourse of the wait, the cleaning process or the capping process on thenozzle-formed surfaces of the droplet ejecting heads 111 is performed,or the regular wastefully ejection process (the regular flushingprocess) is performed.

The accessory apparatus 12 is provided at a side portion (the front sidein the X-axis direction with respect to the main body 2) of the trestle21 and the stone surface plate 22 of the main body 2. As shown in FIG.10, the accessory apparatus 12 has an accessory stand 85 provided on thefloor, a movable platen 86 which can be moved in the Y-axis direction onthe accessory stand 85, a cleaning unit (a cleaner for the dropletejecting heads) 81, a regular flushing unit 82, a capping unit 83, andan ejection-amount measuring unit (a weight measuring unit) 84.

The cleaning unit 81, the regular flushing unit 82, the capping unit 83,and the ejection-amount measuring unit 84 (hereinafter referred to as‘four kinds of droplet ejecting head maintenance units’) are one of thedroplet ejecting head maintenance units used for function maintenance,function recovery, adjustment and inspection of the droplet ejectingheads 111, respectively. In the liquid droplet ejecting apparatus 1according to the present invention, the four kinds of droplet ejectinghead maintenance units are arranged in a group on the movable platen 86as a maintenance-unit installing section (a maintenance-unit installingarea).

As a result of this configuration, the liquid droplet ejecting apparatus1 has high spatial efficiency with respect to the arrangement of thedroplet ejecting head maintenance units, and the entire space of theliquid droplet ejecting apparatus 1 can be effectively utilized so thatthe installation space (the occupied area) required for installing theliquid droplet ejecting apparatus 1 in a plant can be reduced. Inaddition, since the four kinds of droplet ejecting head maintenanceunits are arranged in a group close to each other, the relative movementof the droplet ejecting head maintenance units and the head unit 11 canbe rapidly performed. Thus, unnecessary movement is minimal when thehead unit 11 sequentially uses the droplet ejecting head maintenanceunits. Therefore, the cycle time required for processing one sheet ofthe substrates W can be lessened so that it is possible to enhancethroughput (the production efficiency). The respective droplet ejectinghead maintenance units will be described later.

The accessory stand 85 of the accessory apparatus 12 has a longitudinalshape in the Y-axis direction, and the upper portion (the top surface)thereof is provided with a maintenance-unit moving mechanism 854. Themaintenance-unit moving mechanism 854 has a pair of guides (rails) 851for guiding the movable platen 86 in the Y-axis direction, a ball screw852, and a motor 853 for rotating the ball screw 852, so that themovable platen 86 can be moved (advanced or retreated) in the Y-axisdirection.

As shown in FIG. 11, the movable platen 86 has a top end 861, a bottomend 862, a hoisting mechanism (a height adjusting mechanism) 863 using aball screw, and a hoisting handle 864. The top end 861 can go up anddown with respect to the bottom end 862 by means of the hoistingmechanism 863, and the height of the top end 861 can be adjusted bydriving the hoisting handle 864 to operate the hoisting mechanism 863.The hoisting mechanism 863 is not limited to the manual operation, andmay be operated automatically by providing a driving source such as amotor.

On the top end 861 of the movable platen 86, the cleaning unit 81, theregular flushing unit 82, the capping unit 83, and the ejection-amountmeasuring unit 84 are arranged in a line along the Y-axis direction.Therefore, when the head unit 11 is placed above the accessory apparatus12 by moving the movable platen 86 in the Y-axis direction, one of thefour kinds of droplet ejecting head maintenance units can be selectivelyplaced below the head unit 11, and maintenance by the selected dropletejecting head maintenance unit can be performed on the head unit.

For example, in a state where the movable platen 86 is placed at aposition shown in FIG. 1, since the capping unit 83 is placed below thedroplet ejecting heads 111 of the head unit 11 when the head unit 11 ismoved above the accessory apparatus 12, the capping process can beperformed. In a state where the movable platen 86 is placed at aposition as shown in FIG. 19, since a roller unit 160 (a roller 76) ofthe cleaning unit 81 is placed below the droplet ejecting heads 111 ofthe head unit 11 when the head unit 11 is moved above the accessoryapparatus 12, the cleaning process can be performed on the nozzle-formedsurfaces of the droplet ejecting heads 111. Similarly, the wastefulejection by the regular flushing unit 82 or ejection of liquid dropletsby the ejection-amount measuring unit 84 can be performed.

In this way, in this embodiment, since the four kinds of dropletejecting head maintenance units can be arranged in a line along theY-axis direction by providing the maintenance-unit moving mechanism 854,the side space of the main body 2 can be more effectively utilized, sothat it is possible to shorten the entire X-axis length of the liquiddroplet ejecting apparatus 1.

In this embodiment, the droplet ejecting heads 111 can be replaced bydetaching and attaching the droplet ejecting heads 111 from the maincarriage 61 for each head unit 11. In replacing the droplet ejectingheads 111 (the head unit 11), as shown in FIG. 20, the maintenance-unitmoving mechanism 854 moves the movable platen 86 to the rightmost end inFIG. 20, and then moves the head unit 11 above the accessory apparatus12. Accordingly, since the droplet ejecting heads 111 (the head unit11), detached and attached, and the four kinds of droplet ejecting headmaintenance units on the movable platen 86 do not interfere with eachother, it is possible to replace the droplet ejecting heads 111 (thehead unit 11) easily, rapidly and smoothly.

In this embodiment, when the height of the droplet ejecting heads 111(the head unit 11) is varied correspondingly to the thickness of thesubstrate W by means of the head unit height adjusting mechanism 20, theheight of the respective droplet ejecting head maintenance unitsprovided on the top end 861 can be adjusted by means of the hoistingmechanism 863 in accordance with the height variation, so that it ispossible to easily cope with the height variation of the dropletejecting heads 111 accompanying with the thickness variation of thesubstrate W to be manufactured. Height adjustment (height fitting) ofthe droplet ejecting head maintenance units and the droplet ejectingheads 111 may be performed via up and down movements of the head unit 11by means of the head unit height adjusting mechanism 20.

In this embodiment, the movable platen 86 as the maintenance-unitinstalling section is supported by the accessory stand 85 that isphysically separated from the main body 2. Accordingly, since thevibration generated from the droplet ejecting head maintenance units onthe movable platen 86 or the maintenance-unit moving mechanism 854 canbe prevented from being transferred to the main body 2, it is possibleto avoid an adverse effect on the accuracy of the pattern to be formed(imaged) on the substrate W.

Further, since the size of the stone surface plate 22 can be greatlyreduced, as compared with a case in which the four droplet ejecting headmaintenance units (the movable platen 86) are provided on the stonesurface plate 22, it is possible to reduce the cost for the expensivestone surface plate 22 and to reduce the entire weight of the liquiddroplet ejecting apparatus 1. Furthermore, since positional accuracyrequired for the four droplet ejecting head maintenance units providedon the movable platen 86 is relatively low, accuracy problems areavoided even if the droplet ejecting head maintenance units are notprovided on the stone surface plate 22.

Now, the four droplet ejecting head maintenance units provided in agroup on the top end 861 of the movable platen 86 will be sequentiallydescribed.

FIG. 14 is a perspective view illustrating the roller unit of thecleaning unit of the accessory apparatus shown in FIGS. 10 and 11.

The cleaning unit 81 wipes and cleans, regularly or occasionally, therespective nozzle-formed surfaces of the droplet ejecting heads 111 witha wiping sheet 75.

The wiping sheet 75 has a feature that enable it to suction liquid.Further, its material is not particularly limited, and for example,woven cloth made of polyester can be suitably used.

As shown in FIGS. 10 and 11, the cleaning unit 81 has a wiping sheetsupply unit 150 and a roller unit 160. The wiping sheet supply unit 150comprises a wind-off roller 78 for winding off and supplying the wipingsheet 75, a take-up roller 79 for taking up the wiping sheet 75 afterwiping the nozzle-formed surfaces, and an electric motor for rotatingthe take-up roller 79.

As shown in FIG. 14, the roller unit 160 has a cylindrical roller 76 forpressing the wiping sheet 75 wound off from the wind-off roller 78 onthe nozzle-formed surfaces. The roller 76 is rotatably supported by aroller casing 161. At least the outer circumferential portion of theroller 76 is preferably made of an elastic material, such as rubber,etc., and thus has repulsive elasticity against the pressing force onthe outer circumferential surface (pressing surface). The roller 76 isrotated in synchronism with the supply speed of the wiping sheet 75supplied from the wiping sheet supply unit 150. Here, the rotation ofthe roller 76 is performed by means of an electric motor 163 via apulley 76 c coaxially attached to the end portion of the rotary axis 76a of the roller 76 and a belt 162.

According to this cleaning unit 81, a new cleaning surface of the wipingsheet 75 can be endlessly supplied to the nozzle-formed surfaces of thedroplet ejecting heads 111. Further, since the wiping sheet 75 ispressed on the nozzle-formed surfaces by means of the pressing force ofthe roller 76, it is possible to ensure that the cleaning surface isbrought into contact with the nozzle-formed surfaces.

In the vicinity of the roller 76, a nozzle unit 164 having a pluralityof nozzles (twelve nozzles in the shown configuration) for spraying thecleaning solution onto the wiping sheet 75 before wiping thenozzle-formed surfaces is provided. The nozzle unit 164 is a rod-shapedmember in which a plurality of nozzles are perforated downwardly, and isprovided parallel to an axial line (a rotary axis) of the roller 76. Thewiping sheet 75 wound off from the wind-off roller 78 passes under thenozzle unit 164, under the guidance of the guide roller, not shown, toreach the roller 76. The nozzle unit 164 sprays the cleaning solutiononto the wiping sheet 75 passing under the nozzle unit through thenozzles from the surface side (the top surface). According to thisconfiguration, the wiping sheet 75 before wiping the nozzle-formedsurfaces can suction the cleaning solution, so that the wiping sheet 75can be wet.

The cleaning solution is not particularly limited, and may include, forexample, various cleaning agents or organic solvents. Unlike the shownconfiguration, the nozzle unit 164 may spray the cleaning solution fromthe back surface (the bottom surface) side of the wiping sheet 75.

The respective nozzles formed in the nozzle unit 164 do not communicatewith each other, but are independent from each other. The nozzle unit164 is provided with piping connectors 166 corresponding to therespective nozzles, and the respective connectors 166 are connected tobranching tubules 41 for supplying the cleaning solution to thecorresponding nozzles. The branching tubules 41 are formed out offlexible tubes. The respective nozzles are supplied with a cleaningsolution through the respective branching tubules 41 by means of acleaning solution supply unit 50 that will be described later. In FIG.14, for the purpose of simplification, only three of the twelvebranching tubules 41 are shown.

Since the ejection liquid attached to the nozzle-formed surfaces of thedroplet ejecting heads 111 can be wiped out regularly or occasionally bymeans of the cleaning unit 81, disturbance is prevented from occurringin the ejecting direction (the flying direction) of the liquid dropletsfrom the droplet ejecting nozzles, and thus the liquid droplets can bestraightly sprayed, so that it is possible to form (image) a patternwith high accuracy on the substrate W.

In the cleaning unit 81, the outer circumferential portion of the roller76 may be divided plurally in the rotation axial direction of the roller76, and the outer circumferential surfaces (the pressing surfaces) ofthe divided portions may press the wiping sheet 75 against the dropletejecting heads 111. In this configuration, since the adjacent pressingsurfaces do not interfere with each other in a state where the wipingsheet 75 is pressed against the nozzle-formed surfaces of the dropletejecting heads 111, it is possible to more accurately ensure that thewiping sheet 75 presses against the overall droplet ejecting heads 111.

As shown in FIG. 10, the regular flushing unit 82 has liquid receivers821 for receiving the liquid droplets wastefully ejected from thedroplet ejecting heads 111. The head unit 11 wastefully ejects theliquid droplets from the droplet ejecting heads 111 to the liquidreceivers 821 regularly or occasionally during the waiting time. Thisoperation is performed for the following purposes.

In general, if a large period of time elapses from the pause of theejection of the liquid droplets to the restart of ejection of the liquiddroplets by the droplet ejecting heads 111, the ejecting direction ofthe liquid droplets is disturbed possibly resulting in an amount ofejection that is either too large or too small, and thereby risking thepossibility of an unstable droplet ejecting operation. That is, sincethe ejecting condition is not stable immediately after the dropletejecting heads 111 begin the ejecting process, it is difficult for theliquid droplets to eject properly, and the amount of ejection istherefore not stable. For this reason, by performing the wastefulejection to the liquid receivers 821 during the waiting time, a state inwhich the droplet ejecting head 111 can properly eject the liquiddroplets is maintained.

The liquid receivers 821 are preferably provided with liquid absorbersformed of, for example, a sponge. Liquid droplets ejected wastefully tothe liquid receivers 821 are first absorbed by the liquid absorber.Accordingly, it is possible to more accurately ensure that wastefullyejected liquid droplets do not fly in all directions. The liquidreceivers 821 are connected to suction tubes (not shown), and ejectionliquid gathered in the liquid receivers 821 is recovered through thesuction tubes, and recovered and stored by means of the liquiddischarging unit 18 that will be described later.

FIG. 15 is a perspective view illustrating the capping unit of theaccessory apparatus shown in FIGS. 10 and 11, FIG. 16 is across-sectional view illustrating a state in which caps come intocontact with the droplet ejecting heads, and FIG. 17 is an absorptionpiping system diagram including respective caps in the capping unit.

Now, the capping unit 83 and the absorption piping system thereof willbe described with reference to the above figures.

As shown in FIG. 15, the capping unit 83 has a base plate 831 and twelvecaps 87 arranged on the base plate 831. The respective twelve caps 87correspond to the twelve droplet ejecting heads 111 mounted on the headunit 11, and are arranged in the same arrangement pattern as are thedroplet ejecting heads 111. Accordingly, the respective caps 87 can comeinto (close) contact with and cover the nozzle-formed surfaces of thecorresponding droplet ejecting heads 111.

The capping unit 83 has a supporting portion 832 fixed on the movableplaten 86, and the base plate 831 is supported by the supporting portion832.

The supporting portion 832 is provided with a hoisting mechanism 833employing a pneumatic cylinder for allowing the base plate 831 to go upand down. The caps 87 can go up and down in a group by means of thehoisting mechanism 833.

When the respective droplet ejecting heads 111 of the head unit 11 arecapped with the respective caps 87, the respective caps 87 are firstallowed to be in a down state, and if the head unit 11 is placed abovethe capping unit 83, the respective caps 87 are allowed to go up and arebrought into (close) contact with the respective droplet ejecting heads111. In this state, by activating suction pumps 601, 602, and 603 thatwill be described later, a fluid (gas and liquid) can be suctioned anddischarged from the ejecting nozzles of the droplet ejecting heads 111.

The process of bringing the caps 87 into contact with the dropletejecting heads 111 and suctioning the fluid therefrom (hereinafter,referred to as the ‘capping and suctioning operation’) is performedregularly or occasionally for the following purposes:

(1) to prevent the nozzle-formed surfaces of the droplet ejecting heads111 from drying out when the head unit 11 is in a wait state (during thesupply or removal of the substrate W);

(2) to prevent the clogging of the nozzles of the droplet ejecting heads111 in order to recover an ejection ready state;

(3) to fill the droplet ejecting heads 111 and flow paths with theejection liquid during an initial filling of the ejection liquid;

(4) to discharge the ejection liquid from the droplet ejecting heads 111and the flow paths during replacement of the ejection liquid with adifferent kind of liquid; and

(5) to allow the cleaning solution to flow in the droplet ejecting heads111 and the flow paths during a state in which the cleaning solution hasbeen supplied to the droplet ejecting heads 111, when cleaning thedroplet ejecting heads 111 and the flow paths before replacement of theejection liquid.

As shown in FIG. 16, each cap 87 has a cap body 871 and a cap holder872, and the cap body 871 is biased upwardly by means of two coilsprings 873, and is held by the cap holder 872 to be movable up and downin a predetermined range. A concave portion 874 capable of containing anozzle group formed in one of the droplet ejecting heads 111 is formedon the top surface of the cap body 871, and the edge portion of theconcave portion 874 is provided with a seal packing (a seal member) 875capable of coming in close contact with the droplet ejecting head 111.

The bottom of the concave portion 874 is provided with a liquid absorber876 formed of, for example, a sponge capable of absorbing liquid duringthe state in which the liquid absorber is pressed downward by aframe-shaped pressing member 877. Further, an outlet 878 for dischargingthe fluid suctioned from the droplet ejecting head 111 is formed in thebottom of the concave portion 874, and the outlet 878 communicates withan L-shaped joint 879. The L-shaped joint 879 is connected to a pipe (atube), not shown, constituting a suction flow path 882 that will bedescribed later.

The respective caps 87 are provided with an opening valve 880, and theopening valve can be opened from the bottom side of the concave portion874 to the outside. The opening valve 880 is biased into a closed stateby means of a coil spring 881, and at the final step of the capping andsuctioning operation, the liquid contained in the liquid absorber 876can be suctioned by opening the opening valve 880.

As shown in FIG. 11, the bottom end 862 of the movable platen 86 isprovided with three suction pumps (suctioning force generating source)601, 602, and 603 as suctioning force generating means for generating asuctioning force (negative pressure) in the respective caps 87 (on theinsides of the caps 87). In this embodiment, although the suction pumps601, 602, and 603 comprise piston pumps, respectively, another type ofpump or ejector (vacuum ejectors), etc., may be used as the suctioningforce generating source.

The twelve caps 87 of the capping unit 83 are classified into threegroups, each of which includes four caps. That is, the four caps 87placed at the upper position in FIG. 15 constitute a first group 701,the four caps 87 placed at the vertically middle position in FIG. 15constitute a second group 702, and the four caps 87 placed at the lowerposition in FIG. 15 constitute the third group 703. As shown in FIG. 17,the suction pumps 601, 602, and 603 correspond to the first group 701,the second group 702, and the third group 703, respectively.

The caps 87 are connected to the suction flow paths 882, respectively,and the suction flow paths 882 converge and are connected to the inletsof the corresponding suction pumps 601, 602, and 603, respectively.

In the middle of the respective suction flow paths 882, switching valves(flow path switching means) 883 capable of cutting off the correspondingflow paths are provided. The switching valves 883 can be automaticallyswitched by means of actuators under the control of the control unit 16.

Furthermore, in the middle of the respective suction flow paths 882,pressure sensors (pressure detecting means) 884 for detecting pressurein the corresponding flow paths are provided. Detection results of thepressure sensors 884 are input into the control unit 16, and on thebasis of the detection results, suction errors, etc., in the respectivecaps 87 can be detected and notified, or operation of the suction pumpscan be controlled.

In the capping and suctioning operation, in a state in which byswitching the respective switching valves 883 of the first group 701,the second group 702, and the third group 703, the suction flow paths882 from the caps 87, other than one cap 87 selected from the groups,are cut off, the suction from the selected one cap 87 is performed.While switching the switching valves 883, the sequential suction fromthe four caps 87 of each group is performed.

The pipes connected to the respective discharging outlets of suctionpumps 601, 602, and 603 are merged to form one discharging flow path 885that is connected to a three-way valve (flow path switching means) 886.The downstream side of the three-way valve 886 is divided into adischarging flow path 176 and a discharging flow path 887; thedischarging flow path 176 is connected to a three-way valve (flow pathswitching means) 175, and the discharging flow path 887 is connected toa waste liquid tank (a waste liquid storage unit) 888. The three-wayvalve 886 and the three-way valve 175 are automatically switched bymeans of actuators under the control of the control unit 16.

As described above, when the droplet ejecting heads 111 and the flowpaths are cleaned, a cleaning solution is supplied to the dropletejecting heads 111 of the head unit 11 from a cleaning solution supplymeans, not shown, to perform the capping and suctioning operation (theaforementioned (5)). At this time, the three-way valve 886 is switchedto a state in which a flow is formed from the discharging flow path 885to the discharging flow path 887, and the cleaning solution dischargedfrom the droplet ejecting heads 111 is introduced into and stored in thewaste liquid tank 888.

On the contrary, in the capping and suctioning operation (theaforementioned (1) through (4)) in a normal state in which ejectionliquid is supplied to the droplet ejecting heads 111 of the head unit11, the three-way valve 886 is switched to a state in which a flow isformed from the discharging flow path 885 to the discharging flow path176, and the ejection liquid discharged from the respective dropletejecting heads 111 flows toward the three-way valve 175.

The downstream side of the three-way valve 175 is divided into anintroducing flow path 173 and an introducing flow path 174; theintroducing flow path 173 is connected to a first reuse tank 171, andthe introducing flow path 174 is connected to a second reuse tank 172.The first reuse tank 171 and the second reuse tank 172 are provided inthe tank housing unit 13 as described above.

The ejection liquid flowing from the discharging flow path 176 isintroduced into and stored in the first reuse tank 171 and the secondreuse tank 172 by means of switching of the three-way valve 175.

In this embodiment, the first reuse tank 171, the second reuse tank 172,the introducing flow path 173, the introducing flow path 174, thethree-way valve 175, the discharging flow path 176, the discharging flowpath 885, the three-way valve 886, the discharging flow path 887, andthe waste liquid tank 888 described above constitute a liquid recoveringunit (liquid recovering means) 17.

In this way, the liquid recovering unit 17 transfers the ejection liquiddischarged from the respective droplet ejecting heads 11 in the cappingand suctioning operation, and stores the ejection liquid in the firstreuse tank 171 and the second reuse tank 172, exclusive, without mixingit with different liquid (for example, the ejection liquid obtained fromthe before-imaging flushing unit 104, the regular flushing unit 82 andthe dot-omission detecting unit 19, or the cleaning solution used forcleaning the droplet ejecting heads 111 and the flow paths).

Since ejection liquid recovered into the first reuse tank 171 and thesecond reuse tank 172 is not exposed to the outside and is not incontact with the outside atmosphere until the ejection liquid is firstdischarged from the droplet ejecting heads 111 and is finallytransferred to the first reuse tank 171 or the second reuse tank 172,only a minimal amount of foreign materials, such as refuse, etc., ifany, are mixed thereto, and a solvent is never vaporized to change theconcentration thereof. Further, since different liquids are not mixedthereto as described above, the ejection liquid lies in a good conditionwithout a change in quality due to deterioration or the mixing offoreign materials. Therefore, the ejection liquid recovered into thefirst reuse tank 171 and the second reuse tank 172 can be supplied againto the first primary tank 401 and the second primary tank 402, and canbe reused as ejection liquid to be ejected from the droplet ejectingheads 111. As a result, since the unnecessary amount of consumption ofthe ejection liquid can be greatly reduced, it is possible to reduce themanufacturing cost for the substrate W.

It is preferable that before reusing the ejection liquid recovered intothe first reuse tank 171 and the second reuse tank 172 (before restoringthe ejection liquid to the first primary tank 401 and the second primarytank 402), the ejection liquid be subjected to a process of removingimpurities therefrom (for example, a filtering process using a filter)or a de-aerating process of removing gas dissolved therein (for example,a process of sparkling the dissolved gas under a reduced pressurecondition). As a result, the recovered ejection liquid to be reused willbe in better condition.

Since the liquid recovering unit 17 according to this embodiment usesboth the first reuse tank 171 and the second reuse tank 172 whileswitching between them, the entire capacity can be increased, and it isthus possible to effectively cope with an increase in the amount ofsuction at the time of capping following a growth in size of the liquiddroplet ejecting apparatus 1. Since the entire capacity can be increasedwithout excessively increasing individual capacities of the first reusetank 171 and the second reuse tank 172, excessive weights (specifically,weights when they are full) of the first reuse tank 171 and the secondreuse tank 172 can be avoided, so that it is possible to reduce theburden of an operator when replacing the tanks. By alternately replacing(recovering) the first reuse tank 171 and the second reuse tank 172, itis possible to recover ejection liquid without stopping the operation ofthe liquid droplet ejecting apparatus 1. Therefore, productionefficiency (throughput) can be enhanced.

FIG. 13 is a diagram schematically illustrating a configuration of theliquid amount detecting means. As shown in FIG. 13(b), the liquidrecovering unit 17 further includes liquid amount detecting means 177 afor detecting the amount of liquid in the first reuse tank 171. Theliquid amount detecting means 177 a includes an optically transparenttube 178, of which the inner cavity communicates with the inside of thefirst reuse tank 171 and which is provided vertically outside of thefirst reuse tank 171, and a light-emitting portion 179 and alight-receiving portion 170 facing each other with the tube 178therebetween in the vicinity of the top of the first reuse tank 171.When the amount of liquid in the first reuse tank 171 is increased bymeans of the variation of the amount of light received by thelight-receiving portion 170 to reach a predetermined upper limit level F(full), the liquid amount detecting means 177 a can detect it. Thedetection result of the liquid amount detecting means 177 a is inputinto the control unit 16. The liquid recovering unit 17 furthercomprises liquid amount detecting means 177 b similar to the liquidamount detecting means 177 a, for detecting the amount of liquid in thesecond reuse tank 172.

In the liquid recovering unit 17, the ejection liquid suctioned from thecapping unit 83 is introduced into the first reuse tank 171 in a stateas shown in FIG. 17. Then, when the ejection liquid accumulates in thefirst reuse tank 171 and the liquid amount detecting means 177 a detectsthat the first reuse tank 171 is full, the control unit 16 switches thethree-way valve 175 in accordance with the detection result into a statein which the ejection liquid is introduced into the second reuse tank172.

It is preferable that when the first reuse tank 171 and the second reusetank 172 are full, the control unit 16 notify the operator to replacethe tank (to recover the ejection liquid), for example, similarly to theabove description.

Although two reuse tanks are provided in the liquid recovering unit 17according to this embodiment as described above, the present inventionmay provide a single reuse tank or three or more reuse tanks.

FIG. 18 is a perspective view illustrating the ejection-amount measuringunit of the accessory apparatus shown in FIGS. 10 and 11.

The ejection-amount measuring unit 84 is used for measuring the amountof ejection of the liquid droplets (the amount of one droplet) of thedroplet ejecting heads 111 as a preliminary step before ejecting theliquid droplets to the substrate W (before forming a pattern). In theliquid droplet ejecting system 10, after the amount of liquid dropletsejected from each droplet ejecting head 111 is measured in advance andthe amount of liquid droplets ejected from the respective dropletejecting heads 111 is adjusted to a proper value (a predetermined value)in accordance with the measuring result, the ejection operation isperformed on the substrate W. Accordingly, it is possible to form(image) a pattern with high accuracy.

The timing for performing the measurement and adjustment of the amountof liquid droplets ejected from the droplet ejecting heads 111 is notlimited, and may occur when the liquid droplet ejecting system 10 isfirst activated or when the kind of the ejection liquid is changed. Inaddition, the measurement and adjustment of the amount of liquiddroplets to be ejected may be performed regularly, and may be performedin a substrate unit before the liquid droplets are ejected to thesubstrate W.

As shown in FIG. 18, the ejection-amount measuring unit 84 comprises aplurality of ejection-amount measuring liquid receivers (ejection-amountmeasuring tray) 841 (as many as the droplet ejecting heads)corresponding to the respective droplet ejecting heads 111 of the headunit 11, a plate-shaped support 842 for supporting the ejection-amountmeasuring liquid receivers 841 in a group, and a base 843 fixed to themovable platen 86 to hold the support 842.

The ejection-amount measuring liquid receivers 841 receive the liquiddroplets ejected from the droplet ejecting heads 111 and hold (store)the received liquid. The respective ejection-amount measuring liquidreceivers 841 are detachable to the support 842. In the top surface ofthe support 842, concave portions 844 into which the bottoms of theejection-amount measuring liquid receivers 842 are inserted,respectively, are formed, and thus the ejection-amount measuring liquidreceivers 842 can be positioned and supported in the same arrangement asthe droplet ejecting heads 111.

The support 842 is fixed to the base 843 by means of two thumbscrews 845as fixing members to be detachable thereto. Accordingly, since thetwelve ejection-amount measuring liquid receivers 841 can be detachedand attached in a group for each support 842, it is possible to easilyand rapidly perform the detaching and attaching operation.

When measuring the amount of liquid droplets ejected from the dropletejecting heads 111, the droplet ejecting heads 111 are driven such thatthe head unit 11 is positioned above the ejection-amount measuring unit84, and then the liquid droplets are allowed to be ejected from theejecting nozzles to the corresponding ejection-amount measuring liquidreceivers 841. At this time, the number of liquid droplets ejected fromeach ejecting nozzle is predetermined and is normally about 1 through100,000, and more preferably about 25,000 through 50,000, but the numberis not limited thereto.

In this embodiment, the process of measuring the amount of liquiddroplets ejected from a droplet ejecting head 111 is performed bymeasuring the weight of all of the liquid (overall liquid droplets)received by the corresponding ejection-amount measuring liquid receiver841.

That is, the weights of the ejection-amount measuring liquid receiver841 before and after receiving the liquid droplets are measured, and thedifference between the two measurements is used as the weight of theoverall liquid droplets received by the ejection-amount measuring liquidreceiver 841. Then, by dividing the measured weight by the number ofliquid droplets received by the ejection-amount measuring liquidreceiver 841, the weight of one droplet ejected from each ejectionnozzle is obtained.

When measuring the weight of an ejection-amount measuring liquidreceiver 841, the twelve ejection-amount measuring liquid receivers 841are divided by the number of supports 842, and are placed on a weightmeasuring unit (not shown) provided outside of the liquid dropletejecting system 10. The weight measuring unit comprises a scale, such asan electronic scale, and preferably automatically measures the weight ofeach ejection-amount measuring liquid receiver 841. Alternatively,unlike the above construction, a scale may be provided in theejection-amount measuring unit 84 to measure the weight of eachejection-amount measuring liquid receiver 841 by using the scale.

In this way, when the amount of liquid droplets ejected from the eachdroplet ejecting head 111 is measured, the amount of liquid droplets tobe ejected from each droplet ejecting head 111 is adjusted based on themeasured value. The adjustment of the amount of liquid droplets to beejected from the droplet ejecting heads 111 can be performed by varyingat least one of the amplitude, the frequency, or the driving waveform ofan applied voltage (the pulse-shaped applied voltage) to the drivingelements (piezoelectric elements) provided in the droplet ejecting heads111. Adjustment is performed by means of manipulation of a manipulationpanel (not shown) of the control unit 16.

After the amount of liquid droplets to be ejected from each dropletejecting head 111 is adjusted, the amount of liquid droplets ejectedfrom each droplet ejecting head 111 may be measured again to checkwhether the measured value is a proper value. In this way, in the liquiddroplet ejecting apparatus 1, by repeatedly performing the measurementand adjustment of the amount of liquid droplets ejected from the dropletejecting heads 111 as needed, the amount of liquid droplets to beejected from the droplet ejecting heads 111 is made to be appropriate.

In the liquid droplet ejecting system 10, as described above, theoperation of ejecting the liquid droplets onto the substrate W (theoperation of forming a pattern) is performed in an atmosphere in whichthe temperature and humidity, as environmental conditions, arecontrolled. In general, the amount of liquid droplets ejected from thedroplet ejecting heads 111 are varied in accordance with theenvironmental condition such as temperature, humidity, gaseouscomposition, gaseous pressure, etc., of the atmosphere, even if thedriving conditions of the driving elements are the same. For thisreason, even if the amount of liquid droplets ejected from the dropletejecting heads 111 is measured, when the environmental conditions duringthe measurement differ from the environmental conditions during theactual ejecting of the liquid droplets onto the substrate W, themeasured value generates an error with respect to the amount of liquiddroplets ejected in ejecting the liquid droplets onto the substrate W.Therefore, even if the amount of liquid droplets to be ejected is madeto be appropriate based on the measured value, improvement of theaccuracy is limited.

In consideration of this problem, in the liquid droplet ejecting system10, when the liquid droplets are ejected to measure the amount of liquiddroplets ejected from the droplet ejecting heads 111, that is, when theliquid droplets are ejected to the ejection-amount measuring liquidreceivers 841, it is preferable that the ejection of liquid droplets beperformed in an atmosphere in which the temperature and humidity (theenvironmental conditions) are controlled to be similar to the atmospherein which the actual ejecting of the liquid droplets onto the substrate Woccurs, by adjusting the temperature and humidity (the environmentalconditions) in the chamber 91.

As a result, in the liquid droplet ejecting system 10, it is possible tomore accurately perform measurement of the amount of liquid dropletswithout generating an error with respect to the amount of liquiddroplets ejected in ejecting the liquid droplets onto the substrate W.Further, in the liquid droplet ejecting system 10, by adjusting theamount of liquid droplets based on the accurately measured value to beappropriate, it is possible to accurately (with high accuracy) approach(adjust) the amount of liquid droplets when the liquid droplets areactually ejected onto the substrate W, and it is thus possible to form(image) a pattern on the substrate W with higher accuracy.

In this embodiment, the ejection-amount measuring liquid receivers 841have liquid absorbers 846 such as sponges capable of absorbing thereceived liquid droplets (liquid) therein. As a result, since theejection-amount measuring liquid receivers 841 can hold therein theliquid droplets received from the droplet ejecting heads 111 withoutallowing the liquid droplets to fly in all directions, it is possible tomore accurately perform the measurement without generating a measurementerror. Furthermore, since the received liquid is absorbed by the liquidabsorbers 846, the liquid is not spilled despite the shaking when theejection-amount measuring liquid receivers 841 are detached and attachedfor measuring their weights, so that the handling is facilitated.

The ejection-amount measuring liquid receivers 841 are not limited tothe above configuration, and may have a configuration such that anon-volatile liquid having a specific gravity less than that of thereceived ejection liquid is placed therein in advance and the liquiddroplets are received in the non-volatile liquid.

In this embodiment, the base 843 has a height adjusting mechanism foradjusting the height of the support 842 with a screw. As a result, theheight of the ejection-amount measuring liquid receivers 841 can beadjusted. By appropriately adjusting the distance between the dropletejecting heads 111 and the ejection-amount measuring liquid receivers841 using the height adjusting mechanism, it is possible to moreaccurately ensure that the liquid droplets do not fly in all directions.

The height adjusting mechanism of the ejection-amount measuring liquidreceivers 841 may be constructed to automatically adjust the height bymeans of, for example, a pneumatic cylinder.

FIG. 12 is a piping system diagram illustrating the ejection liquidsupply unit, the cleaning solution supply unit, and the liquiddischarging unit in the liquid droplet ejecting apparatus shown in FIGS.1 and 2; and FIG. 13 is a diagram schematically illustrating theconfiguration of the liquid amount detecting means. Now, the ejectionliquid supply unit 4, the cleaning solution supply unit 50, and theliquid discharging unit 18 in the liquid droplet ejecting apparatus 1will be described with reference to those figures and to FIG. 6.

First, the ejection liquid supply unit 4 for supplying the ejectionliquid to be ejected from the droplet ejecting heads 111 will bedescribed.

As shown in FIG. 12, the ejection liquid supply unit 4 comprises aprimary tank system 40 for storing ejection liquid and one primary flowpath 411 for connecting the primary tank system 40 to a secondary tank412 that will be described later. The primary tank system 40 has a firstprimary tank 401 and a second primary tank 402 provided in the tankhousing unit 13, an outflow pipe 403 connected to the first primary tank401, an outflow pipe 404 connected to the second primary tank 402, and athree-way valve (flow path switching means) 405. The three-way valve 405is connected to the primary flow path 411 and the outflow pipes 403 and404. The ejection liquid supply unit 4 can selectively supply theejection liquid from either the first primary tank 401 or the secondprimary tank 402 to the primary flow path 411 by switching the three-wayvalve 405.

The ejection liquid supply unit 4 further includes pressurizing means406 for supplying pressurized gas to the first primary tank 401 and thesecond primary tank 402, pressurizing pipes 407 and 408 connected to thefirst primary tank 401 to the second primary tank 402, respectively, apipe 410 from the pressurizing means 406, and a three-way valve(pressure path switching means) 409 connected to the above three pipes.As the pressurizing means 406, a pressurized gas source for supplyinggas, such as pressurized nitrogen gas, etc., is used (pressurizing means506, described later, is similar thereto). The ejection liquid supplyunit 4 can selectively pressurize the inside of either the first primarytank 401 or the second primary tank 402 using the pressurizing means406, by switching the three-way valve 409.

As shown in FIG. 6, the secondary tank 412 is fixedly provided in themain carriage 102. That is, the secondary tank 412 is moved in theX-axis direction, together with the main carriage 102. The secondarytank 412 is connected to the other end of the first flow path 411extending from the three-way valve 405, and the ejection liquid of theprimary tank system 40 flows into the secondary tank 412 through thefirst flow path 411.

The first flow path 411 is formed preferably out of a flexible tube. Themiddle portion of the first flow path 411 is provided with a relay unit413 for relaying the primary flow path 411 such that a portion of thesecondary tank 412 side of the primary flow path 411 is movablecorrespondingly to the movement of the secondary tank 412, being movedtogether with the main carriage 102.

The secondary tank 412 and the head unit 11 are connected to each otherthrough twelve secondary flow paths 414 corresponding to the twelvedroplet ejecting heads 111 provided in the head unit 11. That is, thehead unit 11 is provided with the twelve inlets (connection holes) 112corresponding to the respective droplet ejecting heads 111, and theother ends of the twelve secondary flow paths 414 extending from thesecondary tank 412 are connected to the inlets 112, respectively. InFIG. 6, for the purpose of simplification, only two of the twelvesecondary flow paths 414 are shown. Although the secondary flow paths414 are formed of flexible tubes in the shown configuration, thesecondary flow paths are not limited thereto, and may be formed of hardtubes.

The pressure of the secondary tank 412 is controlled by a pressurecontrol unit (a negative pressure control unit), not shown, to benegative. The ejection liquid whose pressure is controlled in thesecondary tank 412 is supplied to the respective droplet ejecting heads111 through the respective secondary flow paths 414. As a result, thepressure of the ejection liquid to be supplied to the respective dropletejecting heads 111 is controlled, so that a good ejecting condition ofliquid droplets in the nozzles of the droplet ejecting heads 111 can beobtained.

Respective middle portions of the secondary flow paths 414 are providedwith cut-off valves 415 for cutting off the respective flow paths. Thecut-off valves 415 cut off the secondary flow paths 414 when thepressure control unit does not work due to any cause, so that theejection liquid flows continuously into the droplet ejecting heads 111at a position lower than that of the secondary tank 412 from thesecondary tank 412, thereby preventing the ejection liquid from leakingfrom the droplet ejecting heads 111.

As shown in FIG. 13(a), the ejection liquid supply unit 4 furtherincludes liquid amount detecting means 416 for detecting the amount ofliquid in the first primary tank 401. The liquid amount detecting means416 includes an optically transparent tube 417, of which the innercavity communicates with the inside of the first primary tank 401 andwhich is provided vertically outside the first primary tank 401, and alight-emitting portion 418 and a light-receiving portion 419 facing eachother with the tube 417 therebetween in the vicinity of the bottom ofthe first primary tank 401.

When the amount of liquid in the first primary tank 401 is decreased bymeans of the variation of the amount of received light in the lightreceiving portion 419 to reach a predetermined lower limit level E(empty), the liquid amount detecting means 416 can detect it. Thedetection result of the liquid amount detecting means 416 is input intothe control unit 16.

The ejection liquid supply unit 4 includes a similar liquid amountdetecting means 420 for detecting the amount of liquid in the secondprimary tank 402. When the amount of liquid in the second primary tank402 is decreased to reach a predetermined lower limit E, the liquidamount detecting means 420 detects it and inputs the detection resultthereof to the control unit 16.

In the ejection liquid supply unit 4 in the state shown in FIG. 12, thefirst primary tank 401 is pressurized by means of the pressurizing means406, and the ejection liquid in the first primary tank 401 is dischargedthrough the outflow pipe 403 and the primary flow path 411 by means ofthe pressure, and supplied to the droplet ejecting heads 111.

When the ejection liquid in the first primary tank 401 is consumed andthe liquid amount detecting means 416 detects that the first primarytank 401 is empty, the control unit 16 switches the three-way valve 405and the three-way valve 409, respectively, based on the detectionresult. Accordingly, the pressurizing means 406 pressurizes the secondprimary tank 402, and the ejection liquid in the second primary tank 402is discharged through the outflow pipe 404 and the primary flow path 411by means of the pressure and is supplied to the droplet ejecting heads111.

In the course of supplying the ejection liquid from the second primarytank 402, an operator separates the empty first primary tank 401 fromthe rack 131, refills the first primary tank with the ejection liquid,and then restores the first primary tank to the rack 131. Thereafter,when the liquid amount detecting means 420 detects that the secondprimary tank 402 is empty, the control unit 16 switches the three-wayvalve 405 and the three-way valve 409, respectively, to allow theejection liquid to be supplied from the first primary tank 401. Then, inthe course of supplying the ejection liquid from the first primary tank401, an operator separates the empty second primary tank 402 from therack 131 and refills the second primary tank with the ejection liquid.

It is preferable that when the first primary tank 401 and the secondprimary tank 402 are empty, the control unit 16 notify the operator toreplace the tank (to re-charge the ejection liquid). The method fornotification may include, for example, a method of displaying charactersor graphic symbols on a manipulation panel (not shown), or a method ofemitting a sound or voice. It is also preferable that an operator benotified as to which primary tank is empty by providing differentcharacters, graphic symbols, sounds, or voices that distinguish betweenthe empty state of the first primary tank 401 and the second primarytank 402.

As described above, since the ejection liquid supply unit 4 according tothis embodiment uses both the first primary tank 401 and the secondprimary tank 402 while switching between them, the entire capacity canbe increased, and it is thus possible to effectively cope with anincrease in consumption of the ejection liquid following a growth in thesize of the liquid droplet ejecting apparatus 1. Since the entirecapacity can be increased without excessively increasing individualcapacities of the first primary tank 401 and the second primary tank402, excessive weights (specifically, weights when full) of the firstprimary tank 401 and the second primary tank 402, respectively, can beavoided, so that it is possible to reduce the burden of an operator whenreplacing the tanks.

Next, the cleaning solution supply unit 50 used in the cleaning unit 81will be described, but the same elements as found in the ejection liquidsupply unit 4 will be not described. As shown in FIG. 12, the cleaningsolution supply unit 50 includes a first cleaning solution tank 501 anda second cleaning solution tank 502 provided in the tank housing unit13, an outflow pipe 503 connected to the first cleaning solution tank501, an outflow pipe 504 connected to the second cleaning solution tank502, a three-way valve (flow path switching means) 505 to which theoutflow pipes 503 and 504 and a liquid supply pipe 511 to the cleaningunit 81 are connected, respectively, pressurizing means 506 forsupplying pressurized gas to the first cleaning solution tank 501 andthe second primary tank 502, a pressuring pipe 507 connected to thefirst cleaning solution tank 501, a pressuring pipe 508 connected to thesecond cleaning solution tank 502, a three-way valve (pressurizing pathswitching means) 509 to which the pressurizing pipes 507 and 508 and apipe (path) 510 from the pressurizing means 506 are connected,respectively, and liquid amount detecting means (not shown) fordetecting the remaining amount of solution in the first cleaningsolution tank 501 and the second cleaning solution tank 502. Thedownstream side of the liquid supply pipe 511 is divided into therespective branching tubules 41 connected to the nozzle unit 164 througha manifold, not shown.

Next, the liquid discharging unit 18 for recovering the dischargedliquid (the ejection liquid) wastefully ejected from the dropletejecting heads 111 in the before-imaging flushing unit 104, the regularflushing unit 82 and the dot-omission detecting unit 19 will bedescribed, but the same elements as found in the liquid recovering unit17, described later, will not be described.

As shown in FIG. 12, the liquid discharging unit 18 includes a firstdischarged liquid tank 181 and a second discharged liquid tank 182 (notshown in FIG. 9) provided in the tank housing unit 13, an inflow pipe183 connected to the first discharged liquid tank 181, an inflow pipe184 connected to the second discharged liquid tank 182, and a three-wayvalve (flow path switching means) 185.

The three-way valve 185 is connected to a liquid discharging pipe 186into which suction tubes (not shown) from the before-imaging flushingunit 104, the regular flushing unit 82, and the dot-omission detectingunit 19 are merged, and the inflow pipes 183 and 184, respectively. Thefirst discharged liquid tank 181 and the second discharged liquid tank182 are provided with liquid amount detecting means (not shown) similarto the liquid amount detecting means 177 a, 177 b, described later,respectively.

In this embodiment, by means of the liquid discharging unit 18, theejection liquid discharged from the before-imaging flushing unit 104,the regular flushing unit 82, and the dot-omission detecting unit 19 isrecovered and stored in common. The ejection liquid recovered from therespective units is exposed once externally in the liquid receivers ofthe respective units, so that foreign materials (refuse) are mixedthereto, or the solvent is vaporized through contact with the externalair to change the concentration thereof. Therefore, the ejection liquidis generally abolished. In this embodiment, since the liquid to beabolished is stored in the first discharged liquid tank 181 and thesecond discharged liquid tank 182 in common, the operation of abolishingthe liquid is completed at the same time, thereby contributing to areduction in labor of an operator.

FIGS. 21 and 22 are perspective views illustrating the fixed sectionsprovided at the side surface of the accessory stand and the relevantpiping components provided therein in the accessory apparatus shown inFIGS. 10 and 11, respectively.

As shown in FIG. 10, the side surfaces of the accessory stand 85 areprovided with fixed sections (side wall sections) 855 and 856 to whichthe relevant piping components are fixed. The fixed sections 855 and 856comprise parts of plate-shaped covers 857 and 858 covering the sidesurfaces of the accessory stand 85. The fixed sections 855 and 856 areplaced at positions receding (recessed) inwardly from the total width(the total width in the X-axis direction) of the accessory stand 85.

As shown in FIG. 21, the fixed section 855 is provided with a clean gasfilter 750, an air filter 751, a mist separator 752, a three-way valve(an air operated valve) 753, a regulator 754, a regulator 755, athree-way valve (an air operated valve) 756, a regulator 757, etc., asthe relevant piping components used for the liquid droplet ejectingapparatus 1.

The air filter 751 and the mist separator 752 remove the foreignmaterial and the liquid droplets contained in the pressurized gas(nitrogen) supplied from the pressurizing means 406, respectively. Thepressure of the pressurized gas passing through the air filter 751 andthe mist separator 752 is adjusted by means of the regulator 757, andthe pressurized gas passes through the clean gas filter 750 and issupplied to the first primary tank 401 and the second primary tank 402.

The pressurized gas supplied from the pressurizing means 406 can besupplied to a pressurized tank (not shown) for storing the cleaningsolution for cleaning the droplet ejecting heads and a pressurized tank(not shown) for storing the cleaning solution for cleaning the flowpaths, by switching the three-way valves 753 and 756. The regulators 754and 755 adjust the pressure of the pressurized gas supplied to thepressurized tank.

As shown in FIG. 22, the fixed section 856 is provided with manifoldvalves 758 and 759, an air supply manifold 760, a regulator for a liquiddischarging process pump 761, a nitrogen discharging manifold 762, anair discharging manifold 763, etc., as the relevant piping componentsused for the liquid droplet ejecting apparatus 1.

The manifold valves 758 and 759 switch the three-way valves in theejection liquid supply unit 4, the cleaning solution supply unit 50, aliquid discharging unit 18, a liquid recovering unit 17, etc., describedabove. The regulator for the liquid discharging process pump 761 adjuststhe suctioning force of a process pump (not shown) provided in theliquid discharging unit 18, for suctioning the discharged liquid. Theair supply manifold 760, the nitrogen discharging manifold 762 and theair discharging manifold 763 divide or merge the pneumatic flow pathsfor operating the aforementioned three-way valves or the pneumaticcylinders provided in the liquid droplet ejecting apparatus 1.

In this embodiment, by fixing various relevant piping components to thefixed sections 855 and 856 placed at the positions receding inwardlyfrom the total width of the accessory stand 85, the relevant pipingcomponents are provided not to be protruded outwardly from the totalwidth of the accessory stand 85. Accordingly, when an operator works inthe vicinity of the accessory stand 85 (during replacement of the headunit 11, maintenance of the apparatus, etc.), it is possible to easilyand smoothly perform maintenance without interfering with the relevantpiping components.

In the liquid droplet ejecting apparatus 1 described above, the fourkinds of droplet ejecting head maintenance units are arranged in a groupon the movable platen 86 as the maintenance-unit installing section, butin the present invention, the dot-omission inspecting unit 19 that is akind of droplet ejecting head maintenance unit may be further arrangedin a group in the maintenance-unit installing section. The dropletejecting head maintenance units are not limited to the five kindsdescribed above, and may include other kinds of droplet ejecting headmaintenance units (having other functions) only if they are used for thefunction maintenance, the function recovery, the adjustment or theinspection of the droplet ejecting heads 111. Further, in the presentinvention, at least three of the plurality of droplet ejecting headmaintenance units may be arranged in a group in the maintenance-unitinstalling section.

FIG. 23 is a plan view schematically illustrating another embodiment ofthe liquid droplet ejecting apparatus according to the presentinvention. Now, another embodiment of the liquid droplet ejectingapparatus according to the present invention will be described withreference to the above figure, but only the differences from theaforementioned embodiment will be briefly described, and the samedetails will be not described.

In a liquid droplet ejecting apparatus 1A shown in FIG. 23(a), thesubstrate-carrying table 3 is provided to be movable in the Y-axisdirection, and the head unit 11 (the droplet ejecting heads 111) isprovided to be movable in the X-axis direction, similarly to theaforementioned embodiment. In a droplet ejecting head maintenance-unitinstalling section 100 positioned below the area in which the head unit11 is moved, the dot-omission detecting unit 19, the cleaning unit 81,the regular flushing unit 82, the capping unit 83, and theejection-amount measuring unit 84 are arranged in the X-axis line in agroup. By moving the head unit 11 in the X-axis direction, the head unit11 can be positioned above the droplet ejecting head maintenance units.In the liquid droplet ejecting apparatus 1A, the maintenance-unit movingmechanism is not necessary, so that it is possible to simplify thestructure thereof.

In a liquid droplet ejecting apparatus 1 B shown in FIG. 23(b), asubstrate table (a work mounting unit) 3′ is provided fixedly in themain body, and a head unit 11′ (droplet ejecting heads 111) is providedto be movable in the X-axis direction and the Y-axis direction,respectively. The liquid droplet ejecting apparatus 1 B can perform theprimary scanning and the secondary scanning by moving the head unit 11′over the substrate table 3′ in the Y-axis direction and the X-axisdirection, respectively.

In the droplet ejecting head maintenance-unit installing section 100 inthe vicinity of the substrate table 3′, the dot-omission detecting unit19, the cleaning unit 81, the regular flushing unit 82, the capping unit83, and the ejection-amount measuring unit 84 are arranged in a group tobe adjacent to each other. By moving the head unit 11′ in the dropletejecting head maintenance-unit installing section 100 in the X-axisdirection and the Y-axis direction, the head unit 11 can be positionedabove the respective droplet ejecting head maintenance units. In theliquid droplet ejecting apparatus 1B, the maintenance-unit movingmechanism is not necessary, so that it is possible to simplify thestructure thereof.

So far, the embodiments of the liquid droplet ejecting apparatusaccording to the present invention have been described, but the presentinvention is not limited to these embodiments. The respective elementsconstituting the liquid droplet ejecting apparatus may be replaced withany element having the same function. Further, any element may be addedthereto.

The Y-axis movement mechanism and the X-axis movement mechanism may use,for example, a ball screw (a feed screw) instead of the linear motor.

Furthermore, in the liquid droplet ejecting apparatus according to thepresent invention, primary scanning and secondary scanning may beperformed by fixing the head unit (droplet ejecting heads) to the mainbody and moving the work (work mounting unit) in the Y-axis directionand the X-axis direction, respectively. That is, it is enough that theliquid droplet ejecting apparatus according to the present inventioncomprises a relative movement mechanism for relatively moving the workmounting unit and the droplet ejecting heads.

An electro-optical device according to the present invention ismanufactured using the liquid droplet ejecting apparatus according tothe present invention described above. A specific example of theelectro-optical device according to the present invention is notparticularly limited, and may include, for example, a liquid crystaldisplay device, an organic EL display device, etc.

Furthermore, a method of manufacturing an electro-optical deviceaccording to the present invention employs the liquid droplet ejectingapparatus according to the present invention. The method ofmanufacturing an electro-optical device according to the presentinvention can be applied, for example, to a method of manufacturing aliquid crystal display device. That is, by selectively ejecting a liquidcontaining filter materials for respective colors to a substrate byusing the liquid droplet ejecting apparatus according to the presentinvention, a color filter in which a plurality of filter elements arearranged on the substrate can be manufactured, and the liquid crystaldisplay device can be manufactured by using the color filter. Inaddition, the method of manufacturing an electro-optical deviceaccording to the present invention can be applied to a method ofmanufacturing, for example, an organic EL display device. That is, byselectively ejecting a liquid containing light-emitting materials forrespective colors to a substrate by using the liquid droplet ejectingapparatus according to the present invention, an organic EL displaydevice in which a plurality of pixels, including EL light-emittinglayers, are arranged on the substrate can be manufactured.

Furthermore, an electronic apparatus according to the present inventioncomprises the electro-optical device manufactured in the aforementionedway. A specific example of the electronic apparatus according to thepresent invention is not particularly limited, and may include apersonal computer, a mobile phone, etc., equipped with the liquidcrystal display device or the organic EL display device manufactured inthe aforementioned way.

1. A liquid droplet ejecting apparatus comprising: a main body; a workpiece mounting unit on which a work piece is mounted; a droplet ejectinghead for ejecting liquid to the work piece; a Y-axis movement mechanismfor moving the work piece mounting unit in a Y-axis direction relativeto the main body, and an X-axis movement mechanism for moving thedroplet ejecting head in an X-axis direction substantially perpendicularto the Y-axis direction relative to the main body; a relative movementmechanism for moving the work piece mounting unit relative to thedroplet ejecting head; droplet ejecting head maintenance units arrangedin a group in a maintenance unit installing section; a maintenance unitmoving mechanism for moving the maintenance unit installing section inthe X-axis direction, and wherein the droplet ejecting head maintenanceunits in the maintenance unit installing section are arranged in a linein the X-axis direction.